So the 350 I have to put in my truck is using oil. When I removed the manifolds to put a different set on it, the bolts all had oil on them and oil was coming out of a couple of holes as well as inside the exhaust holes being dirty as can be except one or two. It’s probably leaking in one or more spots as well but I cannot afford a total rebuild like it actually needs. What do I need to replace to stop the oil from coming out of the exhaust bolt holes? I plan to replace oil pan gasket, rear main seal, and also the valve cover gaskets. Thanks for the help in advance.